Cartridge personal sampling impactor

Abstract

A personal sampling impactor that comprises a compact mounting arrangement using a base, a cover, and an impactor plate cartridge that fits within the cover and is supported on an upper end of the base. A filter is held in place between the impact plate cartridge and the base, and the cover is made so that it can easily be placed over the impaction plate and latched in place to hold the unit together. The cover has inlets that align with a lightly oiled impaction plate surface on which particles will adhere.

What is claimed is: 
     
       1. A personal sampling impactor for sampling aerosols from the atmosphere comprising a base having a peripheral wall defining a chamber, said base having a base wall joining the peripheral wall to close one end of the chamber and define an open top; means at the open top for supporting a filter;   a filter supported on said means for supporting;   an impaction plate cartridge comprising a second peripheral wall having substantially the same shape as the base, and being of slightly smaller lateral size than the base to thereby nest in the base, and an impaction plate support wall joining the second peripheral wall and being supported to overlie the filter and be spaced therefrom when the second peripheral wall is mounted over the open end of the base and resting on the filter, said impaction plate support wall including impaction plate means thereon and having at least one perforation therethrough for permitting air passage therethrough;   an inlet cover defining a third preipheral wall having an inner surface of a size to fit around the second peripheral wall of the impaction plate cartridge, said cover member having an outer end wall joining the third peripheral wall, said impaction cover having inlet means therein for air flow therethrough;   means for holding the cover on the base with the impaction plate cartridge within the cover and supported on the base; and   means for permitting withdrawal of air from the base to establish a flow through the inlet opening, through the impaction plate cartridge, through the filter and out through the means for permitting withdrawal.   
     
     
       2. The apparatus as specified in claim 1 including a means for releasably securing a cover directly on the base comprising at least one pair of ears fixed to said base and extending outwardly therefrom, a pair of mating ears on the cover, said mating ears having slots therein of size to receive threaded members mounted in said ears, and the slots being oriented so that upon twisting the cover the slots will be moved to engage the threadable means. 
     
     
       3. The apparatus of claim 1 wherein said impaction plate support wall has a perforation on a central axis thereof, and said impaction plate means surround the opening and form an annular band therearound. 
     
     
       4. The appparatus as specified in claim 1 wherein said impaction plate support wall has a central solid portion, said impaction plate means being mounted in a central portion, and the at least one perforation comprises a part annular opening to the outside of said impaction plate means and positioned between the impaction plate means and the support wall of the impaction plate cartridge. 
     
     
       5. The apparatus as specified in claim 1 comprising a pair of impaction plate cartridges which are interchangeably fittable within the inlet cover, said impaction plate cartridges comprising the first mentioned impaction plate cartridge wherein the impaction plate support wall has an opening in the center portion thereof, and the impaction plate means is mounted to surround said opening in a substantially annular band, and a second impaction plate cartridge having a second cartridge impaction plate support wall that has an aperture near the outer periphery thereof, and having second cartiridge impaction plate means mounted in the central portions of the second cartridge impaction plate suport wall. 
     
     
       6. A personal sampling impactor comprising: a base forming a cup shape, a filter supported on said base across an open top thereof, and a cover member mounted on said base to define an interior chamber;   inlet means in said cover for providing an air inlet, and an air outlet from said base whereby the air passes across the filter;   impaction plate means mounted within said cover and spaced from said filter, said impaction plate means comprising a plate having at least one aperture therethrough for permitting air flow, and a section of said impaction plate means having an impaction plate surface that is offset laterally from the aperture, said impaction plate surface being aligned with the air inlet in the cover;   the base and cover having a minimum size for providing a flow of air so that the cover can be mounted on a person for sampling air; and   means for removably mounting the cover on said base comprising a pair of ears on the base having cap screw means extending therethrough and being spaced from the outer periphery of the cover, said cover having a pair of ears that mate with the ears on the base and have slots for receiving the cap screws upon a rotary motion of the cover relative to the base to provide a quick attachment feature for the cover.   
     
     
       7. The apparatus as specified in claim 6 wherein said impaction plate means comprises an impaction plate cartridge having a peripheral wall, and an impaction plate support wall joining the peripheral wall to extend across one end of the peripheral wall, said impaction plate support wall comprising a wall having an opening and the impaction plate means mounted thereon, said cartridge being removable from the base when the cover is removed and being retained relative to the base when the cover is in place on the base. 
     
     
       8. The apparatus as specified in claim 7 where impaction means comprises a porous material that will retain a coating of oil thereon.